Although automated dart boards are desirable in homes as well as public locations, it is in public locations that they are used to best advantage. By employing automated scoring, the system knows when a match has commenced and when it has ended. This allows the system to use automated revenue collection means, such as are used in video or arcade games.
It is very important for this type of market to have accurate scoring, combined with a realistic game. Paying customers will not otherwise be satisfied with games that the system provides. Of course, if the games are accurate and realistic then, when placed in a good location, the system will be used a great deal. Thus, it is also desirable for the system to be durable, and for parts that wear to be easily interchangeable. As shown by the art in this field, many attempts have been made to create such a system.
The most successful system has been the type shown in British patent specification 1 532 744 of Jones et al filed May 30, 1977, and published Nov. 22, 1978. Jones discloses a system employing plastic tipped darts and an array of target plates moulded with a large number of closely spaced holes corresponding substantially in size to that of the tip. When the dan is thrown at the board, the tip enters into one of the holes and remains in the hole until removed by one of the players. For automated scoring, a given target plate is slidably supported and, when a given target plate is struck by a dart, the plate slides inwardly to effect closure of an electrical switch contact which directs a signal to a scoring register.
Obviously, the Jones system is not designed to employ regulation grade metal tipped darts of the type preferred by serious dart players. The games are not sufficiently realistic for a wide segment of the market. In addition to the modifications required for reception and retention of grade metal tipped darts, the switches used and the plastic target plate struck by a dart are typically not strong enough to withstand continuous heavy impact from grade metal tipped darts.
Holt et al in U.S. Pat. No. 4,651,998 issued Mar. 24, 1987 discloses a safe tip dart system such as that in Jones et al. Holt et al add a bull's-eye detection mechanism wherein the dan board deforms, or alternatively a plate slides within the board, to actuate a contact switch that causes a timer circuit to activate an audible alarm. This provides an additional attraction for playing the game. The Holt et al bull's-eye provides only a means to actuate a bull's-eye segment and only in conjunction with an all plastic safe tip dan board. As safe tip darts are being used, wear of the segments is not a factor, and no means is discussed for lengthening time between replacement or for facilitating replacement.
Automated regulation dart systems are shown in the following U.S. Pat. No. 4,852,888 issued Aug. 1, 1989 to Ross et al; U.S. Pat. No. 4,244,583 issued Jan. 13, 1981 to Wood et al; U.S. Pat. No. 4,014,546 issued Mar. 29, 1977 to Steinkamp; U.S. Pat. No. 3,677,546 issued Jul. 18, 1972 to Oetiker; U.S. Pat. No. 3,275,321 issued Sep. 27, 1966 to Forest; U.S. Pat. No. 3,101,198 issued Aug. 20, 1963 to Williams. Dart conductive systems have a first conductive layer part of the way into the segment and a second conductive layer further into the segment. The conductive layers are at two different potentials. When the dart enters the segment it pierces the first layer and the second layer which causes current to flow between the layers and indicates the location of the dart. Ross, Forest and Williams disclose modified systems of this type.
Dart conductive systems wear out in the conductive layers as they are continually pierced. As well, darts may not pierce both layers and a score will not be recorded. This can happen when the dart has insufficient energy to reach both layers or the dart enters at an angle. It is also desirable to have the dart create an impulse contact, rather than a constant contact between the conductive layers. This simplifies the operation of circuitry in the system. For a system that operates on a continuous contact see Wood et al. Most dart conductive systems use a mechanical means of moving the dart from contact with o one of the layers or moving one of the layers from contact with the dart. This adds complexity to the mechanical operation of the system. It is an object of the invention to address one or more of these perceived deficiencies in the field or other needs as will become evident from the following description.